Experiments outlined in this proposal are designed to characterize surface polypeptides of the Herpes Simplex Virus (HSV) envelope. Polypeptides which are exposed on the surface of the HSV envelope will be identified by iodination with methyliodohydroxy-benzimidate, followed by SDS-gel electrophoresis and autoradiography. Since some of the polypeptides of the HSV envelope are glycoproteins, characterization of heterosaccharide structures will be performed using lectins as probes. The presence of a particular sugar will be determined by assaying for agglutination of virus particles in the electron microscope after treatment with a variety of lectins. To determine whether a particular sugar moiety is functionally important, sugar moieties identified with lectins will be removed by treatment of HSV with the appropriate glycosidase, after which the treated virus will be tested for infectivity. Viral glycoproteins which carry specific sugar residues will be identified by lectin-affinity chromatography. Surface polypeptides of the HSV envelope, which are identifiid by iodnation, will be purified and characterized and monospecific antiserum will be prepared against each purified polypeptide. Fab fragements prepared from monospecific antiserum will be used as probes to study the fuction of HSV enevlope polypeptides.